Message information storage device



April 19, 1949. O -r5 Y 2,467,566

' MESSAGE INFORMATION STORAGE DEVICE Original Filed Jan. 2, 1941 v 7 Sheets-Shetl .FIG.I I III j INVENTOR LOUIS m POTTS ai i FIMK

7 Sheets-Sheet 2 INVENT OR.

LOUIS II. POTTS L. M. POTTS MESSAGE INFORMATION STORAGE DEVICE April 19, 1949.

Original Filed Jan. 2, 1941 April 19, 1949. 'L. M. POTTS 2,467,566

MESSAGE INFORMATION STORAGE DEVICE Original Filed Jan. 2, 1941 7 Sheets-Sheet :s

r"*"1 V Fl'G-3. F 4- m/ I I I 72 J 24 223 222 26 r "-7 x I L. M. PoTTs I MESSAGE mFonmnoN STORAGE nnvxcn Original Filed Jan. 2; 1941 April 19 1949.

7 Sheets-Sheet 4 I 0.. Ob

8m non J INVENTOR. LOUIS M. POTTS 7 Sheets-Sheet 5 mum INVENTOR. LOUIS M. POTTS A ORNEY.

Ap 19, 1949. L. M. PoTTs MESSAGE INFORMATION STORAGE DEVICE Original Filed Jan. 2, 1941 INVENTOR. LOUIS M. POTTS A ORNEY April 19, 1949- L. M. POTTS 2,467,566

MESSAGE INFORMATION STORAGE DEVICE Original Filed Jan. 2, 1941 7 Sheets-Sheet 7 l4 FIG. l3 FIG. I

ZIG 2'7 FIGBI G2 F|s.3 FIG. I FIG, 2 FIG.3

FIG.9 FIG.4 FIG.9 FIG.4 FIG. 5 FIG. 1

FIG. 11 6 FIG.

FIG. l6 FIG. l2

INVENTOR. LOUIS M. POTTS BY J a A ORNEY.

Patented Apr. 19, 1949 ED TATE UNI PATENT orric s 2,467,566 v mssAGE INFORMATION STORAGE DEVICE Louis M. Potts, Evanstoi i, Ill., assignor to Teletype Corporation, Chicago, 11]., a corporation of Delaware Original application January 2, 1941, Serial No.

372,717. Divided and this application September 20, 1943, Serial No. 503,037

14 Claims. 1

The present application is a division of an application, Serial No. 372,717, filed by Louis M. Potts on January 2, 1941 which has become Patent No. 2,339,803. This latter identified application discloses a system for automatically making a record of communicative connections individually, the record being of such nature that from it an invoice for the communication service may be rendered.

In the operation of manual switching exchange systems in which an accounting record of each communicative connection is made and in which there is no provision of apparatus for producing such a record automatically, an operator ordinarily makes a written record manually of each such connection. With regard to exchange systems provided with automatic switching apparatus for completing communicative connections, manual recording of the accounting information is disadvantageous.

In the accumulation of data for such a communicative service it is necessary that the number of the called and calling stations and the elapsed time of communication be recorded. In order to assemble all of the desired items of information before any final recording is done, it is necessary that a storage device be utilized to record and store the information as it "comes in at various times.

Accordingly, the object of the invention is to provide a storage apparatus wherein the information originating from the different sources and at different times is recorded upon arrival, and stored until such time as all of the information is accumulated when it may be retransmitted to a telegraphic recorder.

The above invention contemplates the recordation by the storage apparatus of permutation code signals and likewise the retransmission of permutation code signals to the telegraphic recorder.

. Two embodiments are contemplated which are hereinafter referred to as the magnetic storage device and the mechanical storage device. The former has been so named as the items of information are magnetically recorded, as permutation code signals, at the rim of a magnetic disc, whereas the latter was so named because an assembly of fingers are individually flexed to correspond to marking and spacing impulses of permutation code signals.

The magnetic storage device includes a rotatable ferro-magnetic disc which may be magnetized under the control of an electromagnet in accordance with alternating current signals. 5 The magnetic disc rotates automatically during intervals, which is necessary to record a particular item of incoming information. The rotation of the magnetic disc is then automatically arrested until that time when a second item of information is ready for recording and storing, when it will again commence to rotat and move through a second interval, whinh als will be followed by a period of rest. There will be as many intervals of rotative movement in one complete cycle of rotation of the magnetic disc as there are different groups of information to be recorded. After all of the information has been recorded and stored on the magnetic disc, the disc is moved through the field of the electromagnet in one complete rotative movement, but this time the magnet acts as a retransmitting magnet and transmits the stored permutation code signals to a printing telegraph unit which records the information, from which a bill may ultimately be made. The magnetic disc is'then rotated through the elec tromagnetic field a third time, this time for the purpose of neutralizing the disc, or in other words, erasing the code signals recorded and stored thereon. Thus, the magnetic disc has now been conditioned to be used a second time. i

The mechanical storage device comprises an assembly of fingers which is positioned by means of a selector mechanism under the control of an electromagnet responsive to permutation code signals. The rotation, of the finger assembly is intermittent, in accordance with the manner in which the items of information are forthcoming. A series of stationary arcuate guides hold the fingers in the position in which they are flexed by the selector mechanism, as they are advanced in step-by-step sequence. The set fingers, in turn, control a series of cams which determine the position of an electrical contact, through which the stored permutation code signals are 45 retransmitted to a telegraphic recorder. After one complete revolution of the finger assembly and the corresponding cam assembly, the fingers are released from their set positions as held by the stationary arcuate members, and once again are free to take a position under the control of the selector mechanism; Thus, the stored signals are completely erased and the fingers are now free to record and store subsequent telephone communication information.

When one or the other of these storage devices I are included in such a system it is necessary that any two subscribers stations may be interconnected and including machine switching apparatus for interconnecting any two subscribers stations, a line identifier device for generating signals representing the station designations of a calling subscriber and of a called subscriber, a transmitting distributor for transmitting the line identification signals not only to be ultimately recorded at the central ofilce for accounting purposes. but also to be recorded at the connected subscribers stations, a master time transmitter for generating signals representing instant time, a signal storing device for storing line, identification signals and time signals, and sequence switching devices for connecting the line identification signal transmitter and the time transmitter to the signal storing device and'for subsequently connecting the storage device to a telegraphic recorder.

For a complete understanding of the invention, reference may be had to the following detailed description to be interpreted in'the light of the accompanying drawings, wherein:

Fig. 1 is a schematic circuit view showing a subscriber's station;

Fig. 2 is a schematic circuit view showing that portion of a machine switching central ofilce station which pertains to the setting up of connections between subscribers stations and the repeating of signals over the communication circuit whencompleted, as well as supervisory and control apparatus pertaining to the line identiilcation apparatus and signal registering apparatus: r

Fig. 3 is a diagrammatic representation of a subscriber's station which maybe identical with that shown in Fig. 1; I

Fig. 4 is a schematic circuit diagram showing the line identifying signal generator, signal transmitter, signal rectifier, and register select ing sequence switch;

Fig. 5 is a combined schematic circuit diagram andmechanical view showing one form ofsignal storing register and a sequence switch, by which the register islcontrolled I jFiglfi is an elevational view; taken at the left Fig.9 is a schematic circuit showing Fig. 12 is a diagrammatic view showing how the sheets of drawings containing Figs. 1, 2, 3, 4, 7, 9, and 11 may be arranged to represent a telegraph communication and accounting recorder;

Fig. 13 is a plan view partly broken away and partly in section showing one of the line identification signal generating transformers:

Fig. 14 is a vertical sectional view taken on the line lll4 of Fig. 13:

Fig. 15 is a diagrammatic plan view of the signal storing register shown diagrammatically in elevation in Fig. '1; and

Fig. 16 is a diagrammatic view showing how the sheets of drawings containing Figs. 1, 2, 3, 4, 5, 9, and 11, may be arranged to represent a complete telegraphic communication and accounting information recorder system. 4

Referring now to the drawings, the reference numeral 2|, Fig. l, designates a subscriber's station, the reference numeral 2!, Fig. 2, designates the line switching and the communication circuit portion of a central ofiice station, the reference numeral 23 designates supervisory and control relay apparatus at the central station, the reference numeral 24, Fig. 23, designates a subscriber's station which may be identical with the station II, the reference numerals 2O, 21, 2., ll (Fig. 4) designate respectively a line identifier signal generating apparatus, a line identification signal transmitting distributor, an electronic rectifier for alternating-current signals generated in 28, and a link'circuit finder switch. In Fig. 5, the reference numeral ll designates generally a message register controlling sequence a switch and the reference numeral 32 designates generally a magnetic type of message register. The reference numerals II and 34 (Fig. 'l) designate respectively a message register controlling sequence switch similar to the switch II in Fig. 5 and a mechanical signal storing register. In Fig. 8 the reference numeral 38 indicates generally a master time transmitter, and in Fig. 9 the reference numeral 31 designates generally a telegraphic recorder and associated controlling apparatus.

Referring now to Fig. 1, the subscriber's station 2| is provided with a recording telegraph printer symbolized by the selector magnet I with which may be associated a telegraph transmitter l2. Printer 4! and transmitter 42 are driven by a motor 43 which has a speed regulator 44 comprising a resistance and a pair of contacts. One end of the winding of selector magnet II is connected to ground and the other end is connected to the upper contact of line relay 4 which has a polarising winding and an operating winding. One end of the operating winding of line relay II, which isthe left-hand winding, is connected to line conductor 41 and the other is connected through the release key ll, break key ll, and transmitting contacts 42 to the front contact of relay I.

I One end of the winding of relay I is connected to ground and the other end is connected to conductor 52 which extends to the upper front contact of relay 3. Upper contact tongue ll of relay is is connected to grounded battery 58 and upon the energization of relay 53 under circumstances which will be described hereinafter, battery 56 will be connected through conductor I! to the winding of relay Ii and to one end of the biasing winding of line relay It, the other end of which is connected to ground, and will also be connected to one end of the winding of audible signal controlling relay '1, to audible signal device 68 through the lower contact tongue II and assodated back contact of relay 51, and to one terminal of direct current motor 43.

Contact tongue 6| of line relay 46 is connected to battery supplying conductor 52 and may engage either its upper contact which is connected to selector magnet 4| or its lower contact which is connected to ground.

The contact tongue 50 of relay 5| which is placed in the circuit of transmitting contacts 42 upon'energization of relay 5| is connected by conductor 62 and conductor 63 to the lower contact associated with the upper right-hand contact tongue 64 of key 66. When key .66 is in normal or unoperated condition, contact tongue 64 engages its lower contact and extends the circuit from conductor 63 through conductor 61, winding of relay 68 to line conductor 69. From this, it will be apparent that the communication circuit at subscribers station 2| includes line conductor 41, operating winding of relay 46, normally closed contacts'of keys 48 and 49,,transmitting contacts 42, contact tongue 50 of ,relay 5|, conductors 62 and 63, contact tongue 64 of key 66, winding of relay 68 and line conductor 69.

Key 66 serves as means for associating a calling dial II with the line conductors 41 and 69. The preparation for dialing is accomplished by rotating the key operating lever in clockwise direction, whereby upper contact tongue 64 is moved out of engagement with its lower contact and into engagement with its upper contact, and intermediate contact tongue I2 and lower contact tongue I3 are moved into engagement with their respective make contacts below them. Left-hand contact tongue I4 of key 66 is not afiected by clockwise rocking of the key operating lever. When key 66 has been operated, a dialing loop is connected across line conductors 41 and 69 from line conductor 41 through conductor I6, intermediate contact tongue I2 of key 66, make contact with which tongue I2 has become engaged, conductor 'II, winding of relay I9, conductor 80, upper contacts 8| of dial II, conductor 83, uppermost contact of key 66, contact tongue 64 of the key, and conductor 61 through winding of relay 68 to line conductor 69. Also through the intermediate contact tongue I2 at the right of key 66, a circuit is completed from ground through contact tongue 50 of relay 5|, conductor 62, conductor 84,

' lower dialing contacts 85, conductor 86, lower contact tongue I8 of relay I9, conductor 11, fixed contact of key 66 and intermediate contact tongue I2 associated therewith, conductor I6, line conductor 41 extending to central ofiice 22 (Fig, 2), branching conductor 81, extreme left-hand contact tongue 88 of cut-off relay 89, back contact associated with contact tongue 88, winding of relay 9| and grounded battery 92. The key 66 also closes a circuit through its lowermost fixed contact and contact tongue I3 from ground through conductor 93, upper contact tongue 94 and back contact of relay I9, lamp 96 to grounded battery 91.

From the foregoing, it will be apparent that the immediate eiiects of operation of key 66 by rotation of its control lever in clockwise direction will be the lighting of lamp 96 to indicate to the subscriber that the apparatus is in condition for dialing and not for telegraph message transmission or reception, and the energization of relay 9| at central office station 22. Single contact tongue 98 of relay BI is grounded and is engageable upon energization of relay 9Iwith a front contact connected to one end of the winding of relay 99, the other end of which isconnected to grounded battery It. Relay 99 may be designated as-a start relay for themachine switching apparatus at central ofiice station 22 and upon being energized attracts its three contact tongues I02, I03, and I04 into engagement with their front, Contact tongue I02 of relay 99 is encontacts. gageable with its front contact to complete a circuit from ground through contact tongue I06 and back contact of relay 89, conductor I01, contact tongue I02 of relay 99, conductor I08, winding of line finder subgroup relay I09 to grounded battery I I I. The machine switching apparatus or line finder indicated by the apparatus enclosed in dotted line rectangle H2, operates in a manner disclosed in Singer Patent No. 1,958,930, granted May 15, 1934, and indue course, the line finder brushes connect with line conductors 41 and 69 and with local conductor H3.

Line finder H2 in operated position forms a holding circuit for holding the connected line 41 from grounded battery H4 through the winding of cutofi relay 89, front contact and contact tongue I04 of relay 98, conductor H6, line finder H2, conductor I I1, and dotted line branch circuit II8 to ground. The dotted line branch circuit H8 includes subsequently effective release apparatus which is fully disclosed in the hereinbefore identified Singer patent, but a detailed explanation of its operation is not considered essential to an understanding of the present invention. Cutoff relay 89 thus becomes energized and attracts its previously identified contact tongues 88 and I06 and its contact tongues H9 and I2I. Contact tongue H9 moves into engagement with a front contact which is connected directly to the winding of relay 89. The. contact tongue is connected directly to conductor I I1 so that a holding circuit for relay 89 is established directly through conductor H1 and branch circuit II 8 to ground. Contact tongue I 06 moves out of engagement with its back contact and thus disconnects ground from the previously identified energizing circuit for line finder magnet I09, whereby the magnet becomes de-energized with its brushes engaging the line conductors 41 and 69 and the holding circuit of relay 89. Contact tongue 88 opens the energizing circuit for relay 9| which, in turn, releases its contact tongue 98, thus opening the energizing circuit for relay 99 which becomes deenergized. Thus, all of the contact tongues of relay 99 are released after relay 89 has become energized and held.

With brush contact in line finder H2 engaged with the bank contacts associated with line conductor 41, the circuit of the line conductor which has been previously traced from the grounded back contact of relay 5| at the subscribers station 2| (Fig. 1) through the winding of relay 9| now extends through the bank contact and brush of line finder H2, conductor I22, make-before-break front contact I23 of relay I20, fixed contact I24 with which front contact I23 co-operates, conductor I2'I, upper winding of repeater relay I28, contact tongue I29 of repeater relay I30, back contact with which contact tongue I29 is normally engaged, conductor I3I, right-hand winding of differential relay I32 to grounded battery I33. Repeater relay I28 is polar and normally holds its contact tongue I34 in engagement with its front contact. However, upon completion of the circuit, from ground at the subscribers station 2| to battery I33, current traverses the upper or line winding of relay I28 in a direction to urge its contact tongue I 34 into engagement with its back contact which is connected to mark- 7 lbattery. 'lheengalementofabrmhinline finder Iii withthebankcontacttowhichline conductor isconnectedresultsintheextension of the circuit of line conductor ll through the bank contact and brush of line finder ill, conductor I, left-hand winding oi polar relay m,

contact tongue and back contact oi relay iii and contact tongue and back contact of relay I to grounded battery I", the connection of which between the left-hand winding of relay I32 and ground is opposite to that of battery III with respect to the right-hand winding of relay III and ground.

Since, as previously described, line conductor 41 is now connected to line conductor ll through conductor It, middle contact tongue I! and associated fixed contact of key tl, conductor 11. winding of relay ll, upper contact ll of dial 1i, uppermost fixed contact and upp r contact tongue N of key It, conductor 61, winding of relay CI to line conductor 0, all at subscriber's station 2|, current fiows through the Joint influence oi batteries III and Ill through the two windings of polar relay I32, through the winding of relays I and it at subscriber's station 2i.

At the subscriber's station the relay ll attracts both of its contact tongues, thus opening the circuit of lamp It which becomes extinguished and also disconnecting branch conductor ll of line conductor 41 from the grounded back contact of relay ll. Relay it is polar and the direction of flow of current produced by the batteries ill and III in series is such as to maintain the contact tongue of relay it in the position in which it is shown; namely, out of engagement with the single fixed contact with which it may co-operate.

Relay I", the winding of which is connected to contact tongue I oi repeater relay III. is an impulsing relay, the function of which is to operate machine switching or line finding mechanism Ill which may be similar to line finding mechanism H2. The manner in which impulsing relay I controls line finder mechanism I" is not disclosed herein but a full and complete disclosure of the impulsing operations and their efiect u'pon line finder ill is disclosed in the hereinbeiore identified Singer patent and in Patent No. 2,088,750 granted August 3, 1937, to 1". S. Kinkead. It is considered sufilcient for the present purposes to state that when contact tongue I of repeater relay ill has moved into engagement with its back contact, which is the condition when the circuit of the operating winding of relay III is completed from the ground at the back contact of relay ii of sulficriber's station II to battery It! at central ofilce 22, or from battery I 3| to battery Ill through the dialing loop at subscriber's station II after relay It has been operated to disconnect the local ground, impulsing relay I" will be energized and will attract its contact tongue into engagement with its front contact, whereas when the dialing loop circuit is broken by opening of the dial contacts due to operation of dial It, the contact tongue of impulsing relay ill will be oscillated in accordance with the dialing impulses It is to be noted that from the contact tongue ill of repeater relay I20 a communication circuit comparable with that comprising line conductors 41, I22, and i2! extends through the upper winding of repeater relay Ill, conductor I, contact us normally engaged by a make-before-break front contact iii of relay I", and conductor III to a brush of line finder ill. Also, the line comprising conductors ti and I" is extended to line finder I" by conductor it" which is connected to the same end of the left-hand winding of polar relay I32 that is connected to contact tongue of relay I31.

As impulsing relay ill (Pig. 2) is operated under the control of dial ll of subscriber's station 2| (Fig. 1). the line finder I" is operated until the brushes associated with the conductors ill and illl have been brought into engagement with bank contacts connected to the conductors I" and ill, respectively, which are associated with the line circuit of station 24 (Fig. 3) which the subscriber at station 2| has dialed, Associated with line finder Ill are relays I", III, and Ill corresponding to relays 80, II. and ll. respectively. when the line finder I" has completed the connection of line conductors Ill and I. with line conductors I" and Ill, respectively, a relay ill corresponding to relay I of the Singer patent is energized over a circuit not shown in the drawings associated with the present specification, but fully shown and described in the Singer patent, and the relay I62 attracts its contact tongue into engagement with its single front contact to connect ground through the secondary winding of an alternating current transformer III, the function of which will be described later, and through the winding of a relay I, thence through a conductor Ill, brush and bank contact of line finder I", conductors Ill and Ill and thence through winding of relay ill to grounded battery I". Thus, a holding circuit for the communication through line finder I" is established by the energlzatlon of the circuit of relay Ill and through contact tongues and front contacts of the relay III, the line conductors I" and I", are connected to the line conductors ill and Ill, respectively, which extend to the subscriber's station 24 (Fig. 3) which may be identical with the subscriber's station (Fig. l)

In Fig. 2, the battery associated with the front contact of repeater relay III has been shown as connected by means of a dotted line. Likewise, the connection from contact tongue I" of repeater relay I28 to the upper winding of repeater relay ill has been shown in dotted line. This is intended to indicate that battery is not at all times connected to the front contact of repeater relay I28 and that contact tongue I of relay Ill is not at all times connected to the operating winding of repeater relay I. As disclosed in the patent to Kinkead, the connections indicated in dotted lines are completed as an incident to the energization of the holding relay ill for the line finder I41. From this point on in the present specification, it is to be assumed that the front contact of repeater relay III is connected to its battery and that the contact tongue Ill 0! relay Ill is connected to the operating winding of repeater relay I30. I

The completion of the circuits of the repeater described in the foregoing paragraph results in the establishment of a communication circuit through the subscriber's station 24 (Fig. 3) traced to front contact of the unoperated relay corresponding to relay Another line circuit extends from grounded battery I39 at the central oflice station 22, back contact and contact tongue of relay I38, back contact and contact tongue of relay I31, conductor I486, brush and bank contact of line finder I41, conductor I51, left-hand front contact and contact tongue of operated relay I59, line conductor I12 to the subscriber's station 24 and continuing at that station through the winding of the polar relay corresponding to relay 68 at station 2 I, upper contact tongue and lower associated contact of unoperated key corresponding to the key 66, conductors corresponding to the conductors 63 and 62 of station 2| to the contact tongue of unoperated relay corresponding to the relay 5| and thus engages ground. The direction of flow of current from battery I39 through the relay at station 24 corresponding to relay 69 at this time is such as to hold the contact tongue of the relay out of engagement with its single contact. No current flows through the operating winding of repeater relay I 39 dueto the fact that the circuit is open at a front contact of the unoperated relay corresponding to relay 5| of station 2|. However, current flows from the battery associated with the back contact of relay I28 through contact tongue I34, biasing winding of relay I36 and artificial line to ground as a result of which contact tongue I29 of relay I30 is attracted into engagement with its front contact, thus substituting battery I16 for battery I33 in the line circuit which includes line conductor 41 extending to subscriber's station 2| (Fig. 1).

Battery I16 is connected in reversed polarity from battery I33 and so opposes battery I39, thus creatin substantially a no-current condition in the dialing loop circuit at subscriber's station 2|.

The completion of connections through line finder I41 also results in momentary operation of relay I38 as fully disclosed in the patent to Kinkead to substitute battery I11 connected to the front contact of relay I38 for battery I39 in the dialing loop extending through station 2| and also at the end of conductor I486 extending from station 24. Battery I11 is so connected as to assist battery I16, whereupon current flows through the dialing loop at station 2| and through polar relay 68 in a direction opposite to that in which current flowed prior to the substitution of battery I16 for battery I33. The flow of current through polar relay 66 is momentary but is of sufiicient duration to move the grounded tongue of polar relay 69 into engagement with the single fixed contact of the relay, thus completing a circuit from ground through the contact tongue, conductor I18, winding of relay 53 to grounded battery 56. A holding circuit for relay 53 is completed through its lower contact tongue I19 and front contact, conductor I93 and closed contacts I84 to ground, so that the relay 53 will remain energized after current reversing relay I39 has returned to normal condition and contact tongue of polar reay 68 at subscriber's station 2| has returned to its right-hand position, as shown. The reversed current flows through the left-hand winding only of relay 32 and may result in operation of its contact tongue, but as no circuit is at this time prepared for completion through the contact tongue, the incidental operation of relay I32 will be idle.

Upon the energization of relay 53, its upper contact tongue 54 which is connected to battery 56 moves into engagement with its front contact which is connected to conductor 52. Thus, battery is connected to audible signal device 68 through the back contact and lower contacttongue 59 of relay 51, to relay 51 which does not become energized because the circuit of its winding is open at the left-hand contact tongue 14 of key 66, to motor 43 which is set in operation, to the biasing winding of polar line relay 46, to the tongue of line relay 46 and to the winding of relay 5|, which is grounded at its opposite end. Substitution of battery I11 for battery I39 also reverses the flow of current through conductor I488, conductor I51, line conductor I12 extending to subscriber's station 24 to the ground engaged by the back contact of the unoperated relay corresponding to relay 5|. Thus, the tongue of the polar relay at station 24 corresponding to the relay 68 is reversed to efiect energization oi. the relay corresponding to relay 53, whereby battery is connected to the audible signal device, to the relay corresponding to relay 51, to the operating motor at station 24, to the biasing winding of its polar line relay, to the tongue of the line relay and to the relay corresponding to relay 5| Thus, at both stations the circuit of line relay 46 and transmitting contacts 42 is extended through the contact tongue 56 of relay 5| and through conductors 62 and 63 to the lower of the two contacts with which the upper contact tongue 64 of key 66 co-operates. At station 2| the tongue at this time is out of engagement with that contact due to the fact that key 66 is operated. The energization of the biasing winding of line relay 46 does not reverse the position of the contact tongue from that shown, and, therefore, battery is extended to the selector magnet 4| of the receiving printer to effect initiation of rest condition in the selector magnet preparatory to receiving telegraph signals. At the station 24 the relay corresponding to relay 5| becomes energized and completes the signaling loop through the polar line relay and through the transmitting contacts because the key corresponding to key 66 is presumed to be unoperated at this time.

The operation of the audible signal device 58 at subscriber's station 2| indicates to the subscriber that a communication circuit has been completed to the remote subscriber's station 24 and that both stations as well as central oflice apparatus have been prepared for the transmis sion of signals. It is necessary for the operator at station 2| to restore key 66 to normal condition in order to disable the dialing loop and to complete the signal transmission loop from lineconductor 41 to line conductor 69 by restoring upper contact tongue 64 of key 66 to engagement with its lower fixed contact. In order to disable audible signal device 59 so that it will not continue to operate during signal transmission, the operator at station 2| may rock the operating lever of key 66 in counterclockwise direction be yond its normal position to efiect momentary engagement of left-hand contact tongue 14 with its fixed contact. This completes the circuit of relay 51 which attracts its lower contact tongue 59 to open the circuit of audible signal device 59 and which also attracts its upper contact tongue |8| to complete a holding circuit for the relay 51, whereupon key 66 may be restored to normal position. At station 24 the audible signal device corresponding to the signal device 59 indicates to the subscriber at that station that the station has been connected to a calling subscriber. The key corresponding to key 66 is presumed to be in normal position but the subscriber at station 24 may disable the audible signal device by momentarilyrocking the operating lever of key It in the direction to close contacts for completing the circuit of the relay corresponding to the relay 51, which establishes for itself a holding circuit and remains energized. The subscriber at station 2] does not immediately initiate transmission of signals to station 24, as in accordance with the present invention there is provision for an answer-back to be recorded at the station 2| which is the identity of the subscriber's station 24 to which station 2| has been connected.

Reference has previously been made to the energisation of relay I82 which attracts its contact tongue to complete a circuit for the energization of relay I from ground through the secondary of alternating current transformer I", contact tongue of relay "2, winding of relay ill, conductor I, brush and bank contact of line finder I", conductors I81 and iii, winding of relay I", and battery I" to ground. Relay I has a single contact tongue "2 which is connected to one terminal of a condenser I92, the other terminal of which is connected to ground. Contact tongue I02 normally engages its back contact which is connected to grounded battery Ill. Thus, condenser I" normally carries a charge applied by battery I and upon energization of relay Ill, condenser ill discharges through contact tongue "2, conductor I, winding of relay "1, conductor ill, and back contact and contact tongue I" of relay 2" to ground. The impulse supplied by condenser I82 energizes relay I91 which establishes a holding circuit from battery 202 through inner contact tongue 203 and front contact and winding of relay I91, conductor It! and contact tongue I" of relay 2 to ground. Outer contact tongue 2 of relay I91 is engageable with a grounded front contact to complete an energizing circuit through the winding of switching relay 2" to grounded battery 201. Switching relay 2" remains energized as long as the holding circuit of relay I11 is energized and attracts three contact tongues 228, 2, and 2 into engagement with their associated front contacts, the function of which is to control the transmission of line identification signals from a line identifier apparatus, which will now be described.

Referring now to Fig. 4, the reference numeral 2| designates a line identification signal generator apparatus which, according to the preferred embodiment of the invention, consists of five sets,

of alternating current transformers, each set of which consists of five transformers lit. One of the transformers is shown in detail in Figs. 13 and 14 to which reference may now be had.

The transformer 2i includes a rectangular core 2 providing a closed magnetic path. One

of the long sides of core 2l1 carries a secondary winding 2". The transformer 2H5 is enclosed in an open ended cylindrical electromagnetic shield 2|! which is provided with diametrically opposed elongated slots 22l parallel to the axis of cylindrical shield 2|! and not longer than the longitudinal dimension of the opening in rectangular core member 2i1.

A plurality of single conductors, such as the conductors 222 and 223, are arranged to serve individually as primaries for the transformers 2 l t. Any one of the conductors, such as 222 or 223 serves as primary only for selected ones of the transformers. A conductor which is arranged to serve as primary for a particular one of the transformers 2it e'nters the transformer through one of the slots MI in the electromagnetic shield 2 ll, threads the core 2l1 next to the secondary winding Ill and emerges from the a t. insformei' through the diametrically opposedslot. 'The'conductor 222 in Fig. 14 is an example of a conductor serving a transformer as primary.' A conductor which is not to serve a particular transformer as primary extends across the outside ofthe electromagnetic shield 2 l I and is prevented by theshield from influencing the core andsecondary: winding within the shield. The conductor222 in1 igni4 is an example of a conductor which does not serve the transformer 2|! as primary. l 'ig. 13 shows ,one of the transformers ill withapluralityof single conductors, the. first; second, third; sixth,

seventh, and eleventh of which, co'untingafrmn,

the left, serve the transformer 2i as primaries, and the fourth, fifth, eighth, ninth and tenth of which pass across the outsideof shield 2i. and are not enabled to influence the transformer withintheshield. m- .X:

In Fig. 4, the relation of the single conductors, such as the conductors 222:and:22t-to.the five setsof transformers III is shown: It is to be noted that each of the single conductors'serves some of the transformers as primaries andpasses around the outside of the shield of the remainder of the transformers. The relation of anyone of the single conductors, such asthe conductors 222 and 228, to the transformers 2|! of oneset, represents a permutation code combination, -the transformers which the conductors serve as primary representing a marking condition and the transformers which a conductor does not serve as primary representing a spacing condition. Thus, the relation of any one of the single conductors to the five sets oftransformers 2i represents five permutation code signal combinations.

At their terminals, as shown at the bottom of Fig. 4, all of the single conductors, such as 222 and 228, are connected to individual condensers 224, the opposite sides of which are connected to ground. Tracing single conductor 222 backwardly from the point at whichit begins to be associated with the first of the transformers 2", it will be noted that it is connected to the right-hand front contact of relay II. From this point, a circuit may be traced through conductor 22! over which line finder holding rela'yJl became energized, innermost right-hand front contact of relay II, and inner right-hand contact tongue. and thence through bank contact andbrush of line finder H2 and over conductor H1, condenser 22l to one endof the secondary winding of an alternating current transformer 221, the other end of which is connected to ground. From the secondary winding of transformer 221, the conductor 222 is adapted to receive alternating current which, traversing the conductor 222 will induce an alternating voltage in those ofthe transformers III which the conductor 222 serves as primary, whereas those which the conductor does not serve as primary will not be influenced-by the alternating current traversing the conductor. The single conductor 22! which has been shown in dotted lines solely for the purpose ofdistinguishing it from conductor 222 as the two conductors traverse the transformers 2|. extends back to the junction of conductor I81 with conductor Ill and the circuit may be traced through conductor I, winding of relay us, contact tongue and front contact of relay "2 to one end of the secondary of transformer I", the other end of which is connected to ground. It is to be noted with reference to both of the circuits for 'supplying alternating current to the line identi-.

ing current, namely, the secondaries of the alternating current transformers, are connected to the brushes of the line finders and may be connected to the bank contacts associated with any of the subscriber's lines, whereas the single conductors, such as 222 and 223, terminate at bank contacts in the line finders and are, therefore, individual to the subscribers communication circuit. It is to be understood that there is a single conductor for controlling the line identification transformers associated with every set of subscribers line connecting apparatus. Each of the I alternating current transformers I63 and 221 has a primary winding which becomes connected to a source of alternating current 228 through sequence switch 3| (Fig. 5) as will presently be described.

Referring again to Fig. 4, there is a transmitting distributor 21 associated with the line identifier apparatus 26. At the right of the transmitting distributor 21 is a row (which in actual practice would probably be a ring) of segments insulated from each other. A local source of alternating current 23I is connected through transformer 232 to certain of the distributor segments, as will be developed in the following description.

The first segment at the top of the row of segments is that engaged by the distributor brush when distributor brush arm 233 is at rest, it being understood that brush arm 233 is arranged to be frictionally driven from a constantly rotating shaft, preferably through a friction clutch. In the idle condition of distributor 21, brush arm 233 is held arrested by stop arm 234 controlled by magnet 2360. The first segment is connected to transformer 232, the local source of alternating current and the segment therefor represents a marking or rest condition. The second segment has no electrical connection and represents spacing or start condition. The next five segments are connected to transformer 232 in permutation code manner to represent the shift or figures signal combination and these are followed by a segment connected to transformer 232 to represent a stop impulse. Next, there is a start segment after which five segments are connected to the secondary windings of the five transformers 216 in the first set followed by a segment connected to transformer 232 as a stop impulse segment pertaining to the permutation code signal generated in the first set of trans formers. Thereafter, the next three sets of transformers 2l6 have their secondaries connected to individual segments, each set of connections being preceded by a free segment representing a start impulse and being followed by a segment connected to transformer 232 representing a stop impulse. Following the stop impulse segment for the fourth set of line identification transformer segments, there is a start impulse segment followed by five segments connected to transformer 232 to represent unshift or letters signal combination. The letters signal combination group of segments is followed by a stop segment connected to transformer 232. Following the last mentioned stop segment, there is a start segment after which the remaining five segments are connected to the five transformers amplifier and detector or rectifier 28.

in the final group of line identification transformers. The first four sets of transformers 216 provide permutation code signal combinations of alternating current representing four figures assigned to designate a subscribers station, and

the permanently applied shift signal combination preceding the segments connected to the first group of transformers 2| 6 provides a signal for conditioning a telegraph printer to print figures corresponding to the code combination. The final group of transformers M6 is intended to provide code combinations representing letters which serve asa classification designation for a subscriber's station, and the permanently coded segments preceding the last group of transformers provide an unshift signal combination in order to condition a telegraph printer for recording letters.

The extreme right-hand brush is connected electrically to an adjacent brush which engages a conductive strip 2340 which is coextensive with a strip of single segments but which has the portion that is coextensive with the last six segments insulated from the remainder of the strip. The portion of distributor strip 2340 which is coextensive with all but the last six segments of the row of segments is connected by conductors 236 i and 231 to the input circuit of a vacuum tube The p0rtion of strip 2340 which is coextensive with the last six segments is connected by conductor 238 to contact tongue 239 of relay 2. Back contact of relay 241 which is normally engaged by contact tongue 239 is connected by conductor 242 to conductor 231 which extends to the input circuit of rectifier 28, so that signals generated in the last set of transformers 2l6 will or will not be applied to the input circuit of the electronic rectifier, depending upon whether or not relay 241 remains deenergized at the time that the brushes traverse the segments.

The two left-hand brushes of distributor 21 are electrically connected together and engage strips which have no electrical connection with the exception of their short segments 243 and 244 which are insulated from the main bodies of the strip and are coextensive only with the last of the segments in the row at the extreme right of the distributor. Segment 244 is connected to ground, while segment 243 is connected to a brush of sequence switch 29, as will be described later.

The output or plate circuit of electronic rectifier 28, which has been shown diagrammatically as a single stage, but which would in practice requir amplification stages, includes the winding of a relay 246 which is energized when the electronic rectifier has alternating current applied to the grid thereof from one of the segments inthe row at the right of distributor 21. When the right-hand brush of the distributor engages a segment which is not connected to the transformer 232 or which is connected to the secondary of a transformer 216 that is not energized from one of the single conductors, such as 222 and 223, th relay 246 will be de-energized. Relay 246 operates contact tongues 241 and 248 both of which are connected to grounded batteries, the latter contact tongue being connected to battery through an adjustable resistance.

Link circuit finder switch 29 has six banks of contacts engaged by six contact brushes numbered 25l, 252, 253, 254, 256, and 251. Brush 25l is connected by conductor 258 to the front contact with which contact tongue 248 of line identification signal responsive relay 246 co-operates. Brush 252 is connected by conductor 259 to one end of the winding of start magnet 2360 for distributor 21, the other end of which is connected to grounded battery 261. Brush 253 is connected by conductor 262 to segment 243 of distributor 21. Brush 254 is connected by conmam ductor III to the back contact with which contact tongue Il'l'ot relay Ill co-operates. Brush Ill is connected by conductor Ill to one end of, the winding of stepping magnet Ill lor the se quence switch Il and also to interrupter contact ton e Ill operated by the stepping magnet. The other end of the winding or stepp l magnet Ill is connected to grounded battery Ill. The final brush I" is connected by conductor Ill to one end of the winding of relay Ill, the other end which is connected to grounded battery Ill.

Before proceeding with the description or the connections to the banks or contacts of the finder switch II. the function of which is to select the particular supervisory and control apparatus associated with a link-circuit connection between two subscribers stations to provide for the transmission or line identification signals pertaining to the two interconnected subscribers to the i nal storing register associated with that supervisory and control apparatus, it appears advisable to describe the sequence switch II which controls the storing oi successive code signals which ulti-- mateiy provide records for accounting purposes.

,Bequence switch Il comprises seven banks of ping magnet III is connected to grounded battery Ill. Brush I'll is connected by conductor Ill through the winding of polarized relay Ill then through the winding of polarized relay III to ground. Brush I'll is connected by conductor III to the lower fixed contact of polarized relay Ill. Brush Ill is connected by conductor III to brush Ill. ,Brush III is connected to ground.

The polarized relays Ill and Ill and the relay Ill control the magnetic signal recorder indicated generally by the reference numeral II (Pig. 5). As shown in Figs. 5 and 6, a rotatable shalt Ill carries a disc I" to which rotation may be imparted i'rom shalt Ill through friction clutch Ill. Disc Ill is o! term-magnetic material suitable Ior magnetic recording and may be magnetized in accordance with an audible frequency oscillatory current flowing in the winding III to magnetize the poles III or an electromagnet Ill. Disc Ill is rotatable between the opposed poles Ill or the electromagnet so that magnetic fiuxflowing from one to the other of the two poles shall traverse the disc I". Magnetic recording apparatus of this general type is well known. One end of the winding oi eiectromagnet Ill is connected to ground and the other end is connected to the contact tongues of polarised relays Ill and Ill. The contact tongue of relay Ill normally engages the lower fixed contact which has no electrical connection. The contact tongue is movable into engagement with an upper contact which is connected to the secondary or an alternating current transformer III, the primary of which is connected to a local source of alternating current. The oppositeend oi' the sec-1 ondary or transformer Ill from that connected to the contact of relay Ill is connected to the; movable contact of a potentiometer Ill across 16 which is connected battery Ill. The mm ol the source or direct current comprising battery Ill and potentiometer Ill-is to bias the magnetizing current to enable utilisation of the steepest portion or the magnetization curve. The reason for providing the local source of alternating current is that the magnetic recorder is respone sive only to oscillatory current, whereas the electronic rectifier II and relay Ill associated with .line identification signal transmitter Il deliver direct current signals. Magnetic registering disc I" has secured thereto a stop disc IlI which is provided with a main stop lug III and a plurality oi subordinate stop lugs Ill. A start magnet Ill .hasoneendolitswindingconnectedtogrounded battery and the other end or the winding connected by conductor III to front contact of relay Ill. The single contact tongue associated with 'relay Ill is connected to ground. The armature.

Ill for start magnet Ill is carried by a start and stop lever III which is biased in clockwise direction by spring II I and is operable in counterclockwise direction by magnet Ill. In the idle condition of the magnetic signal register II, relay Ill is de-energized and, therefore, start magnet Ill is de-energized and the start and stop lever Ill is in extreme clockwise position. In this position, the right-hand end or lever Ill is presented in the path of principal stop lug III of stop disc "I and holds magnetic registering disc Ill arrested. when magnet Ill becomes energised, lever Ill is rocked to extreme counterclockwise position, whereby its right-hand end is moved out oi the path of principal stop lug III and magnetic re- I cording disc I" will be rotated counterclockwise by shaft Ill through friction clutch Ill. lering from principal stop lug III, the subordinate stop lugs Ill are at such distance from the axis oi shai't Ill that their path is blocked by the right-hand end of start and stop lever Ill when that lever is held in counterclockwise position by magnet Ill. It follows that ii magnet Ill is energized at the time one oi the subordinate stop lugs Ill approaches lever Ill, the magnetic recording disc I" will be arrested. and will be rei.e.a.sed upon the lie-energization of start magnet Since the operation 01 magnetic register II to record line identification signals is controlled from the sequence switch Il, further attention will now be given to that switch. In the normal or rest position of the switch, the first and second brushes Ill and I'll which are connected to relax Ill and to stepping magnet IlI respectively engage their first contacts in the banks which are free or dead contacts. Thus, in the normal position 01 the switch, relay Ill is de-energised and the stepping magnet III cannot be started or operated under the control oi brush Ill. However, the back contact which the contact tongue Ill of stepping magnet IlI normally engages is connected by conductor III, and branch conductor III to the first contact in the filth bank of contacts, which brush I'll is then engaging.

Thus, a circuit is extended through brush I'll,

conductor III, brush Ill. conductor Ill to the left-hand contact tongue oi a relay Ill. The front contact with which the contact tongue is engageable upon energization of relay I ll is connected to ground whereby the energizing circuit for stepping magnet III is completed upon the energization of relay Ill. The circuit of relay Ill extends from the grounded back contact with which the lowermost contact tongue Ill of relay Ill (Fig. 2) co-operates, through the conductor '3", branching conductor Ill, winding oi relay Dib.

accuse I 17 Iii, conductor 3|! to the sixth contact in the fifth bank of contacts of finder switch 29 (Fig. 4). whichis the bank of contacts with which brush 266 co-operates. As many or the contacts in the banks'of contacts or finder switch 23 as there are link circuit systems including supervisory andcontrol relays. signal storing registers,

and register control sequence switches in the central omce station 22 (Fig. 2) will be connected to such link circuit systems, ignal storing registers,

etc., andgach oi the contacts in the fifth bank,

counting from the top, will be connected to a conductor corresponding to the conductor 3|! and extending through the winding of a relay corresponding to the relay 3l6 and eventually to the lowermost contact tongue of a relay corresponding to the relay 266. In the present disclosure, only one set of connections for the link circuit to the banks of contacts in finder switch 29 has been shown.

It will be apparent that the energizing circuit for relay 3i. (Fig: 5) cannot be completed until briLsh 266 has been stepped in counterclockwise direction to engage the sixth contact in its contact back. The brushes in finder switch 29 have no normal position, but remain in any random position in which they have been left when the finder is released by a link circuit, until called upon to seek connection with another link cir-,

cuit. When the relay 266 o! the link circuit shown herein operates, an energizing circuit for the stepping magnet 266 may be traced from grounded battery 266, winding of magnet 266, interrupter contact tongue 261 and back contact of the magnet'266, conductor 32L to conductor 3" and thus through contact tongue 2 ll of relay 266 to ground. Thus, .upon the energization of switching relay 266 which, as previously described, becomes energized following the operation of relay I62 upon completion of the communication channel from subscriber's station 2| to subscriber's station 24, the stepping magnet 266 becomes enersized. As such sequence switches usually move the stepping pawl along the ratchet to pick up the next tooth or the ratchet in the operating stroke and advance the brushes on the back stroke or the awl when the stepp magnet becomes tie-energized,- the energization of stepping magnet 266 does not immediately eifect the advancement of the brushes 26! to 261, inclusive. Upon becoming energized, the stepping magnet 266 attracts its contact tongue 261 out of engagement with its back contact through which the magnet was energized, thus interrupting the energizing circuit. Accordingly, stepping magne 266 becomes de-energized and steps the brushes to the next contacts of the banks. It is convenient to assume for the purposes of the immediately following description that none or the bank contacts of finder switch 29 ahead oi the sixth has any connection to other apparatus, and, therefore, that the brushes 26i to 261,-inclusive, find no line condition in the first five contacts. The de-energization of stepping magnet 266 results in restoration of its contact tongue 261 to engagement with its back contact/whereby the interrupted stepping magnet energizing circuit is reclosed and the magnet again becomes energized. The stepping pawl then picks-\up the next tooth on thestepping ratchet, the energizing circuit of the stepping magnet is interrupted and the brushes are stepped to the third bank contacts. This stepping operation is repeated until the brushes 26! to 261, inclusive, are stepped into engagement with the sixth bank contacts. .At this point a substitute the winding of magnet 266, conductor 266, brush 266, conductor 3", winding of relay 3" (Fig.6), conductor 3 and conductor 3" to contact tongue 2 of relay 266 to ground The attrac tion by stepping magnet 266 01' its contact tongue 261, therefore, circuit for the steppingmagnet and itremains energized to prevent further stepping of the brushes 26! to 261, inclusive. I

Referring now to the assumption madein the foregoing paragraph as to the electrical isolation of the contacts in sequence switch 29, it may :be stated'that in actual free contacts, but will have connections corresponding to those of the sixth contacts extending .to other apparatus duplicating the apparatus shown in Figs: 2 and 5. The connection of ground to any conductor corresponding to conenergized. It will be apparent from. this that the brush 266 may stop before reaching the segment which is connected to the grounded conductor that started the stepping operation. For example, if the brush encountered a grounded circuit on one of the first five contacts, it would have stopped and waited until the operations to be performed at that position had been performed, after which the circuit which had initiated the advancement of the brushes would again assume control and restart them. Finder switch 29 has no homing control apparatus. It remains in any position until called upon to advance to another Position.

The energization of relay 3i6 (Fig. 5) in series with the stepping magnet 266 for finder switch 29 results in the movement of its left-hand contact tongue into engagement with the grounded front contact whereby a circuit is completed from ound through the front contact and left-hand contact tongue of relay 3l6, conductor 3, first contact and brush 26l of the sixth bank of sequence switch 3|, conductor 293, fifth brush 219 and first bank contact of sequence switch 3 I, con ductor 3l3, conductor 3l2, back contact and interrupter contact tongue of stepping magnet 263 and magnet 263 to battery. Stepping magnet 233 becomes energized and advances its stepping pawl to pick up the next tooth on the stepping ratchet, and also interrupts its own energizing circuit by attracting its contact tongue 284 out of engagement with the backcontact, whereupon the step-v ping magnet 283 becomes de-energized and executes its back stroke to advance brushes 216 to 262, inclusive, from the first to the second contacts of the banks.

In the first bank of contacts the brush 216 engases the second contact which is connected to ground so that relay .29l becomes energized and completes the circuit of start magnet 306 of storing register 32. The magnet attracts its armature lever which permits the disc 291 to rotate. In the second bank of sequence switch 3| brush 216 now engages the second contact which is electrically connected to the third contact and from which a circuit may be traced over conductor of contacts of sequence switch 29 and from that point through brush 263 and conductor 262 to does not interrupt the energizing practice they will not be 322 to the sixth contact of the third bank.

right-hand contact segment 266 of distributor 21. As segment 266 is not at this time engaged by brushes, no circuit is completed through brush 216 through the stepping magnet 266.

The brush 211 now engaging the second contact in the third bank of sequence switch 6|, to which the third contact is completes a conductive path winding of polarized relay 266, polarized relay 266, conductor 261, brush 211. conductor 626, tongue and front contact of relay 6", conductor 626 to the sixth contact of the fourth bank of contacts in finder switch 26, thence through brush 266, conductor 266, to the back contact of rectifier controlled relay 266 to grounded battery. Since, as previously described, the rectifier 26 is at this time rectifying alternating current applied to the uppermost of the segments at the right of distributor 21, representing a marking signal, the contact tongue 261 of relay 266 is out of engagement with its back contact. The contact tongue of polarized relay from ground at the 266 remains in engagement with its lower contact and transformer 266 is not connected to magnet 30L With this arrangement magnet 66I is not energized in response to a marking signal but would be energized in response to a spacing condition. The reason for .this is that disc 261 will not record a signaling condition when at rest, and, therefore, the marking condition is best represented by unenergized condition of the disc 291. Relay 266 is oppositely polarized to relay 266 and its contact tongue is not moved when 4 relay 266 is under theinfluenceof the battery associated with contact tongue 261, so that they respond to opposite polarities of current only.

As shown in Fig. 5, the second contact of the fourth bank of contacts is dead, as are also the third, fourth, fifth-sixth, seventh, and eighth of that, bank so thatno circuit is completed at this, time to contact tongue 216. In the fifth bank of contacts, the second and third contacts are connected together and from them conductor 626 extends to 'one side of the source of alternating current 226 (Fig. 2). Accordingly, a con ductive path may be traced from theright-hand connection to the source of alternating current 228 through conductor 326, second contact of the fifth bank of sequence switch 6i, brush 219, conductor 266. brush 2" to the second contact of the sixth bank of contacts and from there through conductor 621 through primary winding of alternatingcurrent transformer I66 to the left-hand connection of source of alternating current 226. Thus, the brushes 216 and 26l and their second bank contacts complete the circuit for the primary winding of the transformer and alternating current is induced in the secondary winding,

which traverses the circuit comprising front contact and contact tongue of relay I62, winding of relay I66 which is a direct current relay and is not affected by the alternating current, conductor I66 and single line conductor 223 to energize that conductor and, therefore, the secondary windings of certain of the line identification transformers 2l6 (Fig. 4) in accordance with the designation of the station of the called subscriber.

It is to be noted that the energizing circuit throughwhich stepping magnet 263 for sequenc switch 6i was energized to effect stepping of the brushes to the second bank contacts was through the first contacts of the flfth and sixth banks in sequence switch 6i and through brushes 216 and 26L This circuit was interrupted when the brushes stepped to their second positions and,

connected, electrically therefore, there is no energizing circuit for the stepping magnet 266 and the brushes 216 to 262, inclusive, of sequence switch 6|, remain in engagement with their second bank contacts.

5 Brush 262 which is connected to ground now engages the second bank contact in the seventh bank, from which conductor 626 extends to one end of the winding of relay I26 (Fig. 2) from the other end of which conductor 626 extends to the middle front contact of relay 266 now engaged by contact tongue 266 from which conductor Ill extends to the sixth contact of the second bank of contacts in sequence switch 26,

now engaged by brush 262 from which conductor 256 extends to the winding of start magnet 2666 of transmitting distributor 21, so that start magnet 2360 trips the stop arm 266 for brush arm 236 and the brushes begin to traverse the conductive segments and strips of distributor 21. Relay I20 becomes energized in series with start magnet 2360 and attracts its left-hand contact tongue to connect holding battery to the winding of repeater relay I26. The middle contact tongue of relay I20 engages make-before-break front contact I26 and disengages it from fixed contact I26, thereby engaging the contact tongue with conductor I22 which extends to the line conductor 61 of subscribers station 2|.

The middle contact tongue of relay I26 is connected by conductor 662 and thence through conductor 666, upper front contact and upper contact tongue 206 of energized relay 266, conductor 666 to the sixth contact of the first bank in sequence switch 26 (Fig; 4) from which brush 26I extends the circuit of conductor 666 over conductor 266 to the front contact with which contact tongue 266 of relay 266 is now engaged. Thus, the battery connected to contact tongue 266 of relay 266 is substituted for the battery I66 at the central office, so that as contact tongue 266 is oscillated by relay 266, in accordance with the signals impressed upon the segments at the right of distributor 21, line relay 66 at subscribers station 2| will follow such oscillations and will cause the printer represented by selector magnet 6| at station 2I to record the signals generated in line identifier apparatus 26 corresponding to the identiilcation of subscriber's station 26 (Fig. 3) to which subscribers station 2| is connected. Relay "2 may operate its contact tongue during the signaling from relay 266, due to the fact that the left-hand winding becomesenergized and deenergized in accordance with the signals, but no circuit is prepared for completion through the tongue of relay I62 at this time. The identity of the called subscribers station is thus transmitted to the calling subscriber but not to the called subscriber, since that information is of no interest to him, and is also recorded on the magnetic recording disc 261. The speed of rotation of shaft 266 is .such that the first of the subordinate stops 666 will come into engagement with attracted stop lever 666 of the magnetic storing register about the time but not before the time that the brushes of distributor 21 have traversed all of the segments at the right of the distributor and have returned to the stop position.

The signal generated by the last group of line identification transformers 2", represents station classification which is of interest in connection with accounting records at the central ofllce only as to a calling station, but is not of interest to the calling subscriber at station 26. Accordingly, the relay I26 is provided with a right-hand con-- 7 tact tongue connected to ground and engageablc jQ mi 2i with a front contact from which a circuit extends through conductor 3%, sixth contact of the lowermost bank of contacts in sequence switch 29, brush 2E1, conductor 269, winding of relay 2 to grounded battery 215. Relay 2M is thus ener.- gized-to disconnect the portion of the collector ringcoextensive with the last six segments at the right of distributor 21 from the remainder of the collector ring so that a signal corresponding to the classification of the station of the called sub- 7 scriber will not be transmitted to the calling subs'criber at station 2i and will not be recorded on the magnetic storing register 32.

As the left-hand pair of brushes of distributor 21 traverse segments 243 and 264, an energizing circuit for the stepping magnet of sequence switch 3| (Fig. is completed from ground through segment 244, the brushes of the distributor, se ment 243, conductor 262, brush 253 of sequence switch 29, sixth contact of the third bank of contacts, conductor 322, second contact of the second bank of contacts of sequence switch 3I, brush 216, winding of stepping magnet 233 to grounded battery 286. The brushes 215 to 282, inclusive, are thus stepped to the third contact of each bank. The third contact of the first bank of contacts is dead, and the relay 29I is, therefore, released, and thus start magnet armature 309 is released. Since the second and third contacts in the second, third, and fifth banks are electrically connected together in pairs, no circuit changes occur due to stepping of those brushes. Neither does any change occur due to the stepping of brush 218 as it again engages a free or dead contact. In the sixth bank of contacts, brush 28I moves out of conductive relation to conductor 321 and into conductive relation to a conductor 331 which extends to the primary winding of alternating current transformer 221. Thus, the secondary winding of alternating current transformer 221 becomes energized and alternating current is applied through conductor II1, contact tongue H9 of cut-out relay 89, front contact with which contact tongue I I9 cooperates, conductor 226, and conductor 222 which extends to the line identifying apparatus 26 and traverses the transformers 2I6 in permutation code manner to effect energization of the secondaries of certain of the transformers in representation of the identification of the station 2| (Fig. 1).

In the seventh bank of contacts of sequence switch 3 I ground is connected through brush 282 to the third contact of the bank and from that point through conductor 338, winding of relay I52, conductor 339, conductor 329, front contact and middle contact tongue 209 of relay G, conductor 33I, brush 252 of sequence switch 29, conductor 259, winding of start magnet 2380 of transmitting distributor 21 to grounded battery 20I. Thus, the start magnet 2300 is energized in series with relay I52 to release the distributor brush arm 233 for rotation. The function of relay I52 is similar to that of I20 in that it connects the repeating contact tongue 248 of relay 246 associated with rectifier 28 to the line conductor I1I extending to subscriber's station 24 (Fig. 3), and as'the relay I52 disconnects line conductor ill from the repeater at the central signals representing four digits which constitute the identification of station M (Fig. 1) after which the letter shift combination is transmitted, the right-hand distributor brush concluding this transmission when it reaches the seventh segment from the bottom in Fig. 4. The signals rec.- tified in the rectifier 28 are repeated by the relay 233 from contact tongue 241 to the magnetic storing register 32 through polarized relay 239 and from contact tongue 24a to the receiving printer at subscriber's station 26.

During the previously described first cycle of distributor 21, the relay 29I remained energized through brush 215and the second contact of the first bank of contacts, and in turn, held the start-stop magnet 306 energizedto hold the lever 309 in the path of the first of the subordinate stops 304. However, the release of relay 29I and start magnet 306 when the brushes were stepped results in the restoration of start lever to normal position through its spring 3! I. The first subordinate stop lug 304 therefore escapes, and disc 29 1 begins to rotate. As the distributor 21 opcrates, signals representing the identification of the. calling subscriber's station 2| are transmitted to the called subscriber's station 24 and are recorded in the magnetic storing register disc 291.

Relay I52 which is at this time energized has nocontact tongue corresponding to the righthand contact tongue of relay I20. Accordingly, no energizing circuit is completed over conductor 336 and brush 251 of finder switch 29 for relay 24I. It follows that in this cycle of transmitting distributor 21, the portion of the collector ring 2340- which is coextensive with the segments connected to the last group of station identification transformers 2IB is not disconnected from the main body of the ring 2340 and the signal representing the classification of subscriber's station 2| is recorded by the signal storing register 32 and is transmitted to the called subscribers station 24. This last information may or may not beof interest to the called subscriber but since it is desirable to record it in the storing register, there is no particular reason for estopping its transmission to the called subscriber's station.

Just before distributor 21 comes to rest at the end of its second cycle, its left-hand pair of brushes traverse the segments 243 and 244 to complete again a previously identified circuit for the energization of stepping magnet 283 of sequence switch 3I. The brushes 215 to 282, inclusive, are thus stepped to the fourth segment of the banks of contacts with which they cooperate. The fourth contact of the first bank of contacts is connected to ground so that relay 29I becomes energized to effect the presentation of start lever 309 in the path of the second subordinate stop lug 304, and disc 291 is arrested.

The fourth contact of the bank with which brush 216 cooperates is electrically connected to the fifth and seventh contacts of that bank and from the electrically connected contact, a conductor 3 extends to one of the contacts of a pair of stepping or phasing contacts 342 (Fig. 11) associated with a master time transmitter indicated generally by the reference numeral 36, and shown in Figs.'8 and 11. Before proceeding with the description of the master time transmitter;

it is worthwhile tonote that the fourth contact i n t he third, fourth, fifth, and sixth banks is left free or dead. Thus, in the fourth position of brushes'211 to 28I,.inclusive, no circuits will be formed through those brushes. The fourth con- 23 tactinthelast'bankoioontactsinseeuenee switch It is connected by conductorIII to one end of the winding of relay III, the other end of which is connected to grounded battery III. Since brush III is connected to ground. relay to its normal position out of engagement with the grounded front contact, whereby the relay III becomes de-energized. The relay III releases its contact tongues III. III, and II I, all of which move out of engagement with their front contacts. The contact tongues III, III, and III do not engage any back contacts. The contact tongue III interrupts the conductive paths comprising the conductors III and III over which the line identification signals were transmitted to the subscriber's station. This conductive path is at this time inactivgsince distributor I1 is not operating. The contact tongue III breaks the energizing circuit for relays III and III and for start magnet IIII of distributor II, which circuit is energizable only in the first and second steps of brush III. Movement of contact tongue III out of engagement with grounded front contact results in interruption of the circuit through conductors III and III, winding of relay III, conductor III, brush III of finder switch II, conductor III and winding of stepping magnet III for finder switch II to grounded battery III. Thus, the stepping.

magnet III becomes de-energized and brushes III to N1, inclusive, are advanced to the next position. The line identifier apparatus and associated transmitter and finder await call by another link circuit.

Referring now to Fig. 8, the reference numeral III designates a shaft which has secured thereto a gear I" which meshes with pinion III of a constantly operating motor III. Motor III is driven from a time controlled source of alternating current and drives the shaft III at a rate of one-half revolution per second according to the preferred embodiment of the invention. Shaft III has secured thereto an intermittent motion transmitting device comprising a two-toothed gear III with which meshes an idler gear III having an even number of teeth. The faces of the teeth of gear III are indicated by reference numeral III in Figs. 8 and 10. The faces of the two teeth of gear III are full width, and the untoothed portion of the periphery of gear III is of two diameters, the right-hand portion as viewed in Fig. 8 being of full diameter, and the left-hand portion being of reduced diameter. Alternate teeth of idler III are of half width, the missing portions being in registry with the full diameter portion of gear III; The cutaway portions of the teeth of idler III cooperate with the full diameter portion of gear III to provide a locking mechanism whereby idler gear III is prevented from rotating except through the agency same direction as shaft III a distance of two which are secured five code discs III and an intermittent motion gear III similar to the intermittent motion gear III but having two teeth diametrically opposed. Code discs III are provided with code lugs and notches arranged in ten alignments representing the codes for the digits 0, I, I, I, and I sequentially in duplicate. 'nius, upon each revolution of gear III and specifically during an interval representing not more than '90 of revolution, the discs III are rotated one-tenth revolution to present a new alignment of code lugs and notches on the discs III to a predetermined code sensing position which will be identified later, the code presented successively to the sensing position representing units of seconds and specifically 0, 2, I, 6, 8, twice for one revolution of sleeve I".

An idler gear m meshes with and a came;

by the intermittent motion gear III, the idler gear III being rotated one tooth upon each one- 7 half revolution of sleeve III. Idler III has an even number of teeth and secured to it is an idler III meshing with a gear III secured to a sleeve III adjacent to sleeve I" but sleeved on the shaft III. Gear III has twelve teeth according to the preferred embodiment of the invention and is rotated one-twelfth revolution for each operation of idler III by one of the teeth of intermittent motion gear III, or in other words for each onehalf revolution of sleeve III. Sleeve III has secured thereto five code discs having around the periphery thereof code notches and lugsto provide twelve alignments of codes representing the digits 0, 1, 2, 3, 4, 5. sequentially and in duplicate. The codes carried by the discs III represent two complete sequences of tens of seconds from 0 to 15, inclusive. Sleeve III has secured thereto an intermittent motion gear similar to the gear III and provided with two diametrically opposed teeth. Intermittent motion gear II'I meshes with an idler which through an idler integral with it, rotates a gear III having ten teeth. For each one-half revolution of sleeve III, one-tenth of the two teeth of gear III, and the reduced diameter portion of gear III accommodates the half Width but full depth teeth of idler III. A shaft III extending parallel to the shaft III has secured thereto a gear III preferably provided with twenty teeth. It will be apparent that for each revolution of shaft III, which occurs in two seconds, the two teeth of the gear III will rotate idler III a distance of two teeth which will, in turn, rotate gear III carried by shaft III in the revolution is imparted to gear III.

Gear III has secured thereto a sleeve III sleeved on shaft III and having five code discs III providing ten alignments of code notches and lugs representing the digits 0 to 9, inclusive. The alignments of code elements on code disc III represent units of minutes.

Sleeve III has secured thereto a single toothed intermittent motion gear III which, through idlers similar to those previously described, imparts intermittent motion to a sear III which is provided with twelve teeth. Gear III is advanced one tooth distance for each revolution of sleeve III. Gear III has secured thereto a sleeve III which is identical with the sleeve III having code discs providing twelve alignments of code elements in duplicated series from 0 to 5, inclusive, representing tens of minutes in two complete sets. The intermittent motion gear I" secured to sleeve III is a two-toothed gear having the teeth in diametrically opposed relation.

Two-toothed gear I" drives intermittently through pinions similar to the pinions III and III a gear I'll which has twelve teeth. Secured to gear I" is a sleeve III which carries five code discs "I. The code discs I" provide twelve alignments of code elements which represent the digits 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2. The digits represented by these codes designate units of hours There 'is no preceding the first-mentioned 1 because the next hour designation following 12 is 1.

The sleeve 818 has secured thereto an 'lntermit-,

tent motion gear "I which is provided with three teeth nonuniformly spaced. The description of the stepping cycle of intermittent motion gear 88i will be deferred until after the apparatus which it drives has been described. Gear 8" intermittently drives idlers similar to the idiers 88| and 882 and through them imparts intermittent motion to a gear 882 to which is secured the sleeve 888 which carries two sets'of code discs 888 and 888. The gear 882 has twelve teeth and the code discs 888 and 888 provide twelve alignments of two code combinations. The code combinations providedon the discs 888 represent blank and 1. The digit 1 is the only one required to represent tens of hours since it is not. customary to employ a zero preceding a digit representing units of hours up to 9, and except in twenty-four systems of recording or computing time no digits higher than 1 are employed. The blank codes are used when the hour is represented by a single digit in the units position to fill the interval that would ordinarily be employed for transmitting a code representing tens of hours. The codes for blank and 1 are not arranged alternately around the code disc 888, but there are instead twice as many codes for the digit 1 as there are blanks and the arrangement of twelve codes is blank, 1, 1, in four sets. The reason for this uneven distribution of blanks and is is that they must bear a definite relation to codes representing A. M. and P. M. which are contained on the code discs 888.

In order to limit time-signal transmission to essential characters, only codes for. the letters A and P are contained on the code discs 888. these being suflicient to indicate whether a time designation is forenoon or afternoon. Having reference to the sequence of codes on the discs 888, beginning with blank in the first set, the corresponding codes on the discs 888 are A, A, P, P, P, A, A, A, P, P, P, 'A. It will be noted that the codes associated with the blank codes are alternately A, P, A, P. The reason for the irregular arrangement of codes for blank and 1 and for the letters A and P is that it provides a simple mechanism to step the'code discs for the tens of hours and for the forenoon or after-- noon designations from the intermittent motion gear associated with the code discs for the units of hours, since a code must be changed on the discs 388 while a code on the disc 888 remains the same. The reason for this is that time desig-' nations up to 11:59:58, which involves the figure 1 in the tens position, may be A, M., while those following 12, also involving the digit 1 in the tens of hours position, must be designated P. M. Thereafter all codes will be P. M. until 11:59:58, whereas after 12:00, the digit 1 remaining in the tens position, the designation must be restored to A. M. It has been found -that this can be accomplished most simply by doubling the number of codes representing the digit 1 in the tens position of hours and operating the discs" 888 when it is necessary to advance the discs 388, the code on the disc 388 which is advanced into effective position being the same as that which was advanced out of eifective position. It will follow from this that sometimes the code discs 888 are advanced on account of an advancement of discs 888 when it is not necessary to change the forenoon or afternoon designation code which I time representations pertain to forenoon or aftertion in twenty-four hours.

with reference to the forenoon and afternoon designations that since a change from the code noon, it would be necessary for the intermittent motion gear 381 to step the code discs 888 only twice in each twelve hour period, one stepping operation occurring when the units of hours code discs 819 go from 9 to 0 to bring up the code for the digit 1 in the tens of hours positions to represent 10:00:00 o'clock and another when the.

code for the digit 2 on the discs 818 changes to I to represent a change from 12:59:58 to 1:00:00.

o'clock, at which time the code on the tensof hours code discs 888 must be changed'to blank.

It is, however, necessary to provide for a third.

stepping of the code discs 888 from the intermittent motion gear 881 and this operation occurs as the discs 818 for units of hours change from 1 to 2 following 0 in order to reverse the code;

A or P, since the designation following the hour 12 :00 must be different than the designation.

which preceded it. Accordingly, the three teeth on the intermittent motion gear 881 will be so positioned as to step the code discs 888 and 888. along with the advancement of the code discs 819 from 9 to 0, from 1 to 2, and from the same Since the codes on the disc 818 run from 1 I through 9 to 0 and to 2, one twelve hour periodis represented by those discs and, accordingly, the;

code discs 818 make one revolution per period of twelve hours. The twelve code combinations provided by the discs 888 and 888 represent four sets of codes, each set pertaining to a period of twelve hours. The four sets of codes on the disc 888 are identical but those carried by the disc.

888 represent two pairs of sets, since a set for- 2 the forenoon time designation must differ from 45 those of the afternoon time designation. Itwill be apparent from the foregoing that the code discs 888 and 888 make one-quarter revolution per revolution of the disc 818 or one-half revolu- It should be noted for Ato the code for P or the reverse occurs on the stepping of the discs from 11:59:58 to 12:00:00 at noon and again at midnight, which code is to be in efl'ect during the next twelvevariance with common practice for the two occurrences of 12:00:00 oclock 1 nd require that operators shall become familiar with the fact that they are at variance with common practice. Mechanism of considerably greater complexity would be required to effect changing of thelet ter designating the twelve hour period at the first 

